Mercurial > coderloop

     1 (ns coderloop.reverse-seq

     2   (:use [clojure.contrib

     3 	 [duck-streams :only [file-str read-lines]]

     4 	 [str-utils :only [re-split]]])

     5   (:use rlm.shell-inspect)

     6   (:use [clojure [string :only [trim]]]))

     7 

     8 (def c (file-str "/home/r/coderloop-test/reversesequence-c.in"))

     9 (def a (file-str "/home/r/coderloop-test/reversesequence-a.in"))

    10 (def b (file-str "/home/r/coderloop-test/reversesequence-b.in"))

    11 

    12 (defn test-trace-map []

    13   (= [:a :b :c :d :e]

    14        (trace-map {:a :b :d :e :c :d :b :c})))

    15 

    16 

    17 (defn read-name-map

    18   "takes a file of pairs of names and returns a map from the first

    19    element in those pairs to the second element in the pairs."   

    20   [#^java.io.File file]

    21   (let [pairs  (map #(re-split #"\W+" (trim %)) (read-lines file))]

    22     (zipmap (map first pairs) (map second pairs))))

    23 

    24 (defn start-linked-map

    25   "takes a map-representing-a-list and finds the beginning of that list"

    26   [m]

    27   (first (remove (set (vals m)) (keys m))))

    28 

    29 (defn trace-map

    30   "chains through a map-representing-a-list, building a list along the way."

    31   [m]

    32   (loop [index (start-linked-map m)

    33 	 chain (vector index)]

    34     (let [new-index (get m index ::sentinel)]

    35       (if (= new-index ::sentinel)

    36 	chain

    37 	(recur  new-index (conj chain new-index))))))

    38 

    39 

    40 

    41 (if (command-line?)

    42   (dorun

    43    (map println (reverse (trace-map (read-name-map (file-str (first *command-line-args*))))))))
author	Robert McIntyre <rlm@mit.edu>
date	Tue, 18 Oct 2011 01:17:49 -0700
parents
children